The message is blank in the sent email

<?php

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $name = trim($_POST['name']);
    $email = trim($_POST['_replyto']);
    $message = trim($_POST['textarea']);

    if ($name == "" || $email == "" || $message = "") {
        echo "You must specify a value for you name, email adress, and/or message.";
        exit;
    }

    foreach( $_POST as $value ) {
        if( stripos($value, 'Content-Type:') !== FALSE ) {
            echo "There was a problem with the information you entered.";
            exit;
        }
    }

    if ($_POST["address"] != "") {
        echo "Your submission was not added";
        exit;
    }

    require "inc/phpmailer/PHPMailerAutoload.php";

    $mail = new PHPMailer;

    if(!$mail->ValidateAddress($email)) {
        echo "You must specify a valid email address.";
        exit;
    }

    $email_body = '';
    $email_body = $email_body . "Name: " . $name . "</br>";
    $email_body = $email_body . "Email: " . $email . "</br>";
    $email_body = $email_body . "Message: " . $message;

    $mail->setFrom($email, $name);
    $address = 'test@gmail.com';
    $mail->addAddress($address);
    $mail->Subject = 'test Contact Form Submission!';
    $mail->msgHTML($email_body);

    if(!$mail->send()) {
        echo 'Message could not be sent.' . "</br>";
        echo 'Error: ' . $mail->ErrorInfo;         
        exit;
    } 
    header("location: index.php?status=thanks");
    exit;
}

?>